Techniques of culturing grouper in soil ponds

Grouper is delicious in taste and colorful in shape, which is deeply loved by consumers everywhere. At present, cage culture is widely used in our country. With the change of sea environment, there are many diseases in cage culture and it is difficult to control them. Therefore, it is meaningful to popularize grouper pond culture.

1. Pond selection and desilting 1. Pond selection pond area 5 murs 20 mu, a total of 300 mu, pond water depth 2 Mu 6 meters; bottom material is sand or gravel; it is convenient to absorb moisture, the water quality is fresh, there is no domestic and industrial pollution, and the maximum daily water exchange can reach 50%. 2. 2 months before detoxification and seedling, drain the stagnant water of the pond, bask the pond for 2 weeks, and remove the silt impurities on the pond surface; set up artificial reefs with striped stones or stones in the deep water area; install a filter net, enter the water 50 cm, soak and disinfect 150 kg quicklime per mu for 15 days, to kill pathogens and enemy organisms, and flush the pool twice. 2. 20 days before seedling release, the basic bait was fed to 0.4 cm water depth, 500 grams of urea, 50 grams of superphosphate and 25 grams of silicate were applied per mu for 3 times in a row, so that the water color was yellowish green, and then gradually entered the water to 1 meter, and the transparency was maintained at about 0.4 meters. 3. the seedlings of grouper are all from the natural seedlings captured in this area, and the seedlings selected and purchased are caged or fishing. When choosing and buying fished seedlings, those with hook injuries and swallowing hooks should be abandoned. The seedling size is related to the seedling time. The seedling cast in April weighs about 50 grams per tail, and the seedling cast in June weighs about 100 grams. The seedling density was controlled within 667 tails / mu. 4. Feed mainly to fresh mixed fish and shrimp, feed compound feed once a day in the morning and evening when the fresh feed is insufficient, little or no when the water temperature is lower than 13 ℃, and no bait in the overwintering season. The daily feed intake is 8% Murray 10% of the fish body weight in the early stage and 5% Murray 6% in the middle and later stage. The specific feeding amount should be adjusted according to the weather, water quality, feeding situation, residual bait quantity and so on. Generally, the feeding situation should be checked through the bait frame set up, and the principle of eating within 2 hours should be mastered. Regular baiting is done at 6: 00 a. M. and 5: 00 p. M. The feeding site is changed every 10 days to avoid local sediment deterioration and water quality caused by long-term feeding. Water quality management and disease prevention and control 1. Water quality control regularly tests the physical and chemical factors of water quality. By changing water and sprinkling quicklime, the transparency is kept in the range of 0.3ft 0.5 m, the PH value is 7.8mur8.5, the dissolved oxygen is above 5.0 mg / L, the content of ammonia nitrogen is controlled below 0.5 mg / L, and the daily water exchange is about 30%. In the high temperature season, according to the tidal conditions, the water exchange time is arranged in the evening or dawn, and the drainage at noon is avoided as far as possible. 2. Disease prevention and control insist on disinfecting pond water with Yuechongjing 0.3ml 0.5g / m3 once a month to kill parasites; sterilizing pond water with quicklime 25g / m3 or third generation fish and shrimps 0.3ml / m3 once in half a month to kill pathogens; in summer, feeding oxytetracycline or allicin bait for a course of treatment every month to prevent the occurrence of diseases. 6. Culture effect 1. After nearly 2 years of culture, grouper can be harvested. The maximum individual weight of grouper is 0.7 kg, the minimum individual weight is 0.3 kg, and the average individual weight is 0.5 kg. 2. The survival rate of the whole process is about 66.1%. 3. The feed coefficient is 1.7 for compound feed and 8.61 for fresh feed. 4. The average price of economic benefit is about 100yuan / kg, the output value per mu is 23000 yuan, the cost is 13000 yuan, the profit per mu is 10, 000 yuan, and the input-output ratio is 1.75. 7. Other technical points: 1. Grouper has the habit of eating each other, and the seedlings are required to be neat and well-fed at one time. If the individual difference is large, it should be classified into ponds for culture. As the seedlings are caught by hook or cage, 10 mg / L potassium permanganate is used before entering the pond for 10 minutes to kill parasites and bacteria, prevent fish injury and infection, improve the survival rate and prevent the occurrence of diseases. 2. When entering the pond, a filter must be used to prevent enemy organisms from entering the pond. 3. Artificial reefs should be attached to the deep water area of the pond to provide a good habitat for grouper. 4. In order to improve the physique and disease resistance of grouper, the diet containing multivitamins (vitamin C, E, An and trace elements) should be fed regularly in the early stage of culture. 5. In order to prevent the pollution of residual bait to water quality, it is suggested that a small amount of Sparidae fish should be mixed to remove the residual bait and keep the water quality in good condition.